Preface | p. xvii |
Acknowledgements | p. xx |
Principles of Measurement | p. 1 |
Introduction to Measurement | p. 3 |
Measurement units | p. 3 |
Measurement system applications | p. 6 |
Elements of a measurement system | p. 8 |
Choosing appropriate measuring instruments | p. 9 |
Instrument Types and Performance Characteristics | p. 12 |
Review of instrument types | p. 12 |
Active and passive instruments | p. 12 |
Null-type and deflection-type instruments | p. 13 |
Analogue and digital instruments | p. 14 |
Indicating instruments and instruments with a signal output | p. 15 |
Smart and non-smart instruments | p. 16 |
Static characteristics of instruments | p. 16 |
Accuracy and inaccuracy (measurement uncertainty) | p. 16 |
Precision/repeatability/reproducibility | p. 17 |
Tolerance | p. 17 |
Range or span | p. 18 |
Linearity | p. 19 |
Sensitivity of measurement | p. 19 |
Threshold | p. 20 |
Resolution | p. 20 |
Sensitivity to disturbance | p. 20 |
Hysteresis effects | p. 22 |
Dead space | p. 23 |
Dynamic characteristics of instruments | p. 23 |
Zero order instrument | p. 25 |
First order instrument | p. 25 |
Second order instrument | p. 28 |
Necessity for calibration | p. 29 |
Self-test questions | p. 30 |
Errors During the Measurement Process | p. 32 |
Introduction | p. 32 |
Sources of systematic error | p. 33 |
System disturbance due to measurement | p. 33 |
Errors due to environmental inputs | p. 37 |
Wear in instrument components | p. 38 |
Connecting leads | p. 38 |
Reduction of systematic errors | p. 39 |
Careful instrument design | p. 39 |
Method of opposing inputs | p. 39 |
High-gain feedback | p. 39 |
Calibration | p. 41 |
Manual correction of output reading | p. 42 |
Intelligent instruments | p. 42 |
Quantification of systematic errors | p. 42 |
Random errors | p. 42 |
Statistical analysis of measurements subject to random errors | p. 43 |
Graphical data analysis techniques--frequency distributions | p. 46 |
Aggregation of measurement system errors | p. 56 |
Combined effect of systematic and random errors | p. 56 |
Aggregation of errors from separate measurement system components | p. 56 |
Total error when combining multiple measurements | p. 59 |
Self-test questions | p. 60 |
References and further reading | p. 63 |
Calibration of Measuring Sensors and Instruments | p. 64 |
Principles of calibration | p. 64 |
Control of calibration environment | p. 66 |
Calibration chain and traceability | p. 67 |
Calibration records | p. 71 |
References and further reading | p. 72 |
Measurement Noise and Signal Processing | p. 73 |
Sources of measurement noise | p. 73 |
Inductive coupling | p. 74 |
Capacitive (electrostatic) coupling | p. 74 |
Noise due to multiple earths | p. 74 |
Noise in the form of voltage transients | p. 75 |
Thermoelectric potentials | p. 75 |
Shot noise | p. 76 |
Electrochemical potentials | p. 76 |
Techniques for reducing measurement noise | p. 76 |
Location and design of signal wires | p. 76 |
Earthing | p. 77 |
Shielding | p. 77 |
Other techniques | p. 77 |
Introduction to signal processing | p. 78 |
Analogue signal filtering | p. 78 |
Passive analogue filters | p. 81 |
Active analogue filters | p. 85 |
Other analogue signal processing operations | p. 86 |
Signal amplification | p. 87 |
Signal attenuation | p. 88 |
Differential amplification | p. 89 |
Signal linearization | p. 90 |
Bias (zero drift) removal | p. 91 |
Signal integration | p. 92 |
Voltage follower (pre-amplifier) | p. 92 |
Voltage comparator | p. 92 |
Phase-sensitive detector | p. 93 |
Lock-in amplifier | p. 94 |
Signal addition | p. 94 |
Signal multiplication | p. 95 |
Digital signal processing | p. 95 |
Signal sampling | p. 95 |
Sample and hold circuit | p. 97 |
Analogue-to-digital converters | p. 97 |
Digital-to-analogue (D/A) conversion | p. 99 |
Digital filtering | p. 100 |
Autocorrelation | p. 100 |
Other digital signal processing operations | p. 101 |
References and further reading | p. 101 |
Electrical Indicating and Test Instruments | p. 102 |
Digital meters | p. 102 |
Voltage-to-time conversion digital voltmeter | p. 103 |
Potentiometric digital voltmeter | p. 103 |
Dual-slope integration digital voltmeter | p. 103 |
Voltage-to-frequency conversion digital voltmeter | p. 104 |
Digital multimeter | p. 104 |
Analogue meters | p. 104 |
Moving-coil meters | p. 105 |
Moving-iron meter | p. 106 |
Electrodynamic meters | p. 107 |
Clamp-on meters | p. 108 |
Analogue multimeter | p. 108 |
Measuring high-frequency signals | p. 109 |
Thermocouple meter | p. 110 |
Electronic analogue voltmeters | p. 111 |
Calculation of meter outputs for non-standard waveforms | p. 112 |
Cathode ray oscilloscope | p. 114 |
Cathode ray tube | p. 115 |
Channel | p. 116 |
Single-ended input | p. 117 |
Differential input | p. 117 |
Timebase circuit | p. 117 |
Vertical sensitivity control | p. 117 |
Display position control | p. 118 |
Digital storage oscilloscopes | p. 118 |
References and further reading | p. 118 |
Variable Conversion Elements | p. 119 |
Bridge circuits | p. 119 |
Null-type, d.c. bridge (Wheatstone bridge) | p. 120 |
Deflection-type d.c. bridge | p. 121 |
Error analysis | p. 128 |
A.c. bridges | p. 130 |
Resistance measurement | p. 134 |
D.c. bridge circuit | p. 135 |
Voltmeter-ammeter method | p. 135 |
Resistance-substitution method | p. 135 |
Use of the digital voltmeter to measure resistance | p. 136 |
The ohmmeter | p. 136 |
Codes for resistor values | p. 137 |
Inductance measurement | p. 138 |
Capacitance measurement | p. 138 |
Alphanumeric codes for capacitor values | p. 139 |
Current measurement | p. 140 |
Frequency measurement | p. 141 |
Digital counter-timers | p. 142 |
Phase-locked loop | p. 142 |
Cathode ray oscilloscope | p. 143 |
The Wien bridge | p. 144 |
Phase measurement | p. 145 |
Electronic counter-timer | p. 145 |
X-Y plotter | p. 145 |
Oscilloscope | p. 147 |
Phase-sensitive detector | p. 147 |
Self-test questions | p. 147 |
References and further reading | p. 150 |
Signal Transmission | p. 151 |
Electrical transmission | p. 151 |
Transmission as varying voltages | p. 151 |
Current loop transmission | p. 152 |
Transmission using an a.c. carrier | p. 153 |
Pneumatic transmission | p. 154 |
Fibre-optic transmission | p. 155 |
Principles of fibre optics | p. 156 |
Transmission characteristics | p. 158 |
Multiplexing schemes | p. 160 |
Optical wireless telemetry | p. 160 |
Radio telemetry (radio wireless transmission) | p. 161 |
Digital transmission protocols | p. 163 |
References and further reading | p. 164 |
Digital Computation and Intelligent Devices | p. 165 |
Principles of digital computation | p. 165 |
Elements of a computer | p. 165 |
Computer operation | p. 168 |
Interfacing | p. 174 |
Practical considerations in adding computers to measurement systems | p. 176 |
Intelligent devices | p. 177 |
Intelligent instruments | p. 177 |
Smart sensors | p. 179 |
Smart transmitters | p. 180 |
Communication with intelligent devices | p. 183 |
Computation in intelligent devices | p. 184 |
Future trends in intelligent devices | p. 185 |
Self-test questions | p. 185 |
References and further reading | p. 186 |
Instrumentation/Computer Networks | p. 187 |
Introduction | p. 187 |
Serial communication lines | p. 188 |
Asynchronous transmission | p. 189 |
Parallel data bus | p. 190 |
Local area networks (LANs) | p. 192 |
Star networks | p. 193 |
Ring and bus networks | p. 194 |
Gateways | p. 195 |
HART | p. 195 |
Digital fieldbuses | p. 196 |
Communication protocols for very large systems | p. 198 |
Protocol standardization | p. 198 |
Future development of networks | p. 199 |
References and further reading | p. 199 |
Display, Recording and Presentation of Measurement Data | p. 200 |
Display of measurement signals | p. 200 |
Electronic output displays | p. 200 |
Computer monitor displays | p. 201 |
Recording of measurement data | p. 202 |
Mechanical chart recorders | p. 202 |
Ultra-violet recorders | p. 208 |
Fibre-optic recorders (recording oscilloscopes) | p. 209 |
Hybrid chart recorders | p. 209 |
Magnetic tape recorders | p. 209 |
Digital recorders | p. 210 |
Storage oscilloscopes | p. 211 |
Presentation of data | p. 212 |
Tabular data presentation | p. 212 |
Graphical presentation of data | p. 213 |
Self-test questions | p. 222 |
References and further reading | p. 223 |
Measurement Reliability and Safety Systems | p. 224 |
Reliability | p. 224 |
Principles of reliability | p. 224 |
Laws of reliability in complex systems | p. 228 |
Improving measurement system reliability | p. 229 |
Software reliability | p. 232 |
Safety systems | p. 236 |
Introduction to safety systems | p. 236 |
Operation of safety systems | p. 237 |
Design of a safety system | p. 238 |
Self-test questions | p. 241 |
References and further reading | p. 242 |
Measurement Sensors and Instruments | p. 245 |
Sensor Technologies | p. 247 |
Capacitive and resistive sensors | p. 247 |
Magnetic sensors | p. 247 |
Hall-effect sensors | p. 249 |
Piezoelectric transducers | p. 250 |
Strain gauges | p. 251 |
Piezoresistive sensors | p. 252 |
Optical sensors (air path) | p. 252 |
Optical sensors (fibre-optic) | p. 253 |
Intrinsic sensors | p. 254 |
Extrinsic sensors | p. 258 |
Distributed sensors | p. 259 |
Ultrasonic transducers | p. 259 |
Transmission speed | p. 260 |
Direction of travel of ultrasound waves | p. 261 |
Directionality of ultrasound waves | p. 261 |
Relationship between wavelength, frequency and directionality of ultrasound waves | p. 262 |
Attenuation of ultrasound waves | p. 262 |
Ultrasound as a range sensor | p. 263 |
Use of ultrasound in tracking 3D object motion | p. 264 |
Effect of noise in ultrasonic measurement systems | p. 265 |
Exploiting Doppler shift in ultrasound transmission | p. 265 |
Ultrasonic imaging | p. 267 |
Nuclear sensors | p. 267 |
Microsensors | p. 268 |
References and further reading | p. 270 |
Temperature Measurement | p. 271 |
Principles of temperature measurement | p. 271 |
Thermoelectric effect sensors (thermocouples) | p. 272 |
Thermocouple tables | p. 276 |
Non-zero reference junction temperature | p. 277 |
Thermocouple types | p. 279 |
Thermocouple protection | p. 280 |
Thermocouple manufacture | p. 281 |
The thermopile | p. 282 |
Digital thermometer | p. 282 |
The continuous thermocouple | p. 282 |
Varying resistance devices | p. 283 |
Resistance thermometers (resistance temperature devices) | p. 284 |
Thermistors | p. 285 |
Semiconductor devices | p. 286 |
Radiation thermometers | p. 287 |
Optical pyrometers | p. 289 |
Radiation pyrometers | p. 290 |
Thermography (thermal imaging) | p. 293 |
Thermal expansion methods | p. 294 |
Liquid-in-glass thermometers | p. 295 |
Bimetallic thermometer | p. 296 |
Pressure thermometers | p. 296 |
Quartz thermometers | p. 297 |
Fibre-optic temperature sensors | p. 297 |
Acoustic thermometers | p. 298 |
Colour indicators | p. 299 |
Change of state of materials | p. 299 |
Intelligent temperature-measuring instruments | p. 300 |
Choice between temperature transducers | p. 300 |
Self-test questions | p. 302 |
References and further reading | p. 303 |
Pressure Measurement | p. 304 |
Diaphragms | p. 305 |
Capacitive pressure sensor | p. 306 |
Fibre-optic pressure sensors | p. 306 |
Bellows | p. 307 |
Bourdon tube | p. 308 |
Manometers | p. 310 |
Resonant-wire devices | p. 311 |
Dead-weight gauge | p. 312 |
Special measurement devices for low pressures | p. 312 |
High-pressure measurement (greater than 7000 bar) | p. 315 |
Intelligent pressure transducers | p. 316 |
Selection of pressure sensors | p. 316 |
Flow Measurement | p. 319 |
Mass flow rate | p. 319 |
Conveyor-based methods | p. 319 |
Coriolis flowmeter | p. 320 |
Thermal mass flow measurement | p. 320 |
Joint measurement of volume flow rate and fluid density | p. 321 |
Volume flow rate | p. 321 |
Differential pressure (obstruction-type) meters | p. 322 |
Variable area flowmeters (Rotameters) | p. 327 |
Positive displacement flowmeters | p. 328 |
Turbine meters | p. 329 |
Electromagnetic flowmeters | p. 330 |
Vortex-shedding flowmeters | p. 332 |
Ultrasonic flowmeters | p. 332 |
Other types of flowmeter for measuring volume flow rate | p. 336 |
Intelligent flowmeters | p. 338 |
Choice between flowmeters for particular applications | p. 338 |
References and further reading | p. 339 |
Level Measurement | p. 340 |
Dipsticks | p. 340 |
Float systems | p. 340 |
Pressure-measuring devices (hydrostatic systems) | p. 341 |
Capacitive devices | p. 343 |
Ultrasonic level gauge | p. 344 |
Radar (microwave) methods | p. 346 |
Radiation methods | p. 346 |
Other techniques | p. 348 |
Vibrating level sensor | p. 348 |
Hot-wire elements/carbon resistor elements | p. 348 |
Laser methods | p. 349 |
Fibre-optic level sensors | p. 349 |
Thermography | p. 349 |
Intelligent level-measuring instruments | p. 351 |
Choice between different level sensors | p. 351 |
References and further reading | p. 351 |
Mass, Force and Torque Measurement | p. 352 |
Mass (weight) measurement | p. 352 |
Electronic load cell (electronic balance) | p. 352 |
Pneumatic/hydraulic load cells | p. 354 |
Intelligent load cells | p. 355 |
Mass-balance (weighing) instruments | p. 356 |
Spring balance | p. 359 |
Force measurement | p. 359 |
Use of accelerometers | p. 360 |
Vibrating wire sensor | p. 360 |
Torque measurement | p. 361 |
Reaction forces in shaft bearings | p. 361 |
Prony brake | p. 361 |
Measurement of induced strain | p. 362 |
Optical torque measurement | p. 364 |
Translational Motion Transducers | p. 365 |
Displacement | p. 365 |
The resistive potentiometer | p. 365 |
Linear variable differential transformer (LVDT) | p. 368 |
Variable capacitance transducers | p. 370 |
Variable inductance transducers | p. 371 |
Strain gauges | p. 371 |
Piezoelectric transducers | p. 373 |
Nozzle flapper | p. 373 |
Other methods of measuring small displacements | p. 374 |
Measurement of large displacements (range sensors) | p. 378 |
Proximity sensors | p. 381 |
Selection of translational measurement transducers | p. 382 |
Velocity | p. 382 |
Differentiation of displacement measurements | p. 382 |
Integration of the output of an accelerometer | p. 383 |
Conversion to rotational velocity | p. 383 |
Acceleration | p. 383 |
Selection of accelerometers | p. 385 |
Vibration | p. 386 |
Nature of vibration | p. 386 |
Vibration measurement | p. 386 |
Shock | p. 388 |
Rotational Motion Transducers | p. 390 |
Rotational displacement | p. 390 |
Circular and helical potentiometers | p. 390 |
Rotational differential transformer | p. 391 |
Incremental shaft encoders | p. 392 |
Coded-disc shaft encoders | p. 394 |
The resolver | p. 398 |
The synchro | p. 399 |
The induction potentiometer | p. 402 |
The rotary inductosyn | p. 402 |
Gyroscopes | p. 402 |
Choice between rotational displacement transducers | p. 406 |
Rotational velocity | p. 407 |
Digital tachometers | p. 407 |
Stroboscopic methods | p. 410 |
Analogue tachometers | p. 411 |
Mechanical flyball | p. 413 |
The rate gyroscope | p. 415 |
Fibre-optic gyroscope | p. 416 |
Differentiation of angular displacement measurements | p. 417 |
Integration of the output from an accelerometer | p. 417 |
Choice between rotational velocity transducers | p. 417 |
Measurement of rotational acceleration | p. 417 |
References and further reading | p. 418 |
Summary of Other Measurements | p. 419 |
Dimension measurement | p. 419 |
Rules and tapes | p. 419 |
Callipers | p. 421 |
Micrometers | p. 422 |
Gauge blocks (slip gauges) and length bars | p. 423 |
Height and depth measurement | p. 425 |
Angle measurement | p. 426 |
Flatness measurement | p. 428 |
Volume measurement | p. 428 |
Viscosity measurement | p. 429 |
Capillary and tube viscometers | p. 430 |
Falling body viscometer | p. 431 |
Rotational viscometers | p. 431 |
Moisture measurement | p. 432 |
Industrial moisture measurement techniques | p. 432 |
Laboratory techniques for moisture measurement | p. 434 |
Humidity measurement | p. 435 |
Sound measurement | p. 436 |
pH measurement | p. 437 |
The glass electrode | p. 438 |
Other methods of pH measurement | p. 439 |
Gas sensing and analysis | p. 439 |
Catalytic (calorimetric) sensors | p. 440 |
Paper tape sensors | p. 441 |
Liquid electrolyte electrochemical cells | p. 441 |
Solid-state electrochemical cells (zirconia sensor) | p. 442 |
Catalytic gate FETs | p. 442 |
Semiconductor (metal oxide) sensors | p. 442 |
Organic sensors | p. 442 |
Piezoelectric devices | p. 443 |
Infra-red absorption | p. 443 |
Mass spectrometers | p. 443 |
Gas chromatography | p. 443 |
References and further reading | p. 444 |
Imperial--metric--SI conversion tables | p. 445 |
Thevenin's theorem | p. 452 |
Thermocouple tables | p. 458 |
Solutions to self-test questions | p. 464 |
Index | p. 469 |
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